The invention relates to cannulas and, more particularly, to high performance cannulas, where the diameter of the lumen of the cannula can be varied.
Cannulas are used in a wide variety of applications. For example, cannula assemblies are typically used in minimally invasive surgical procedures such as laparoscopic, endoscopic, and arthroscopic procedures. Cannulas can be used to deploy operating instrumentation during such minimally invasive procedures. Additionally, during coronary surgery, venous and arterial cannulas are used to conduct blood between the body and the bypass equipment. Moreover, cannulas are also used as vents, sumps, and for chest tube fluid suction. Cannulas are also used in a variety of non-medical contexts.
In one aspect, this invention involves a cannula having a cannula body with a proximal end, a distal end, and a lumen extending between the two ends. The cannula is made of a flexible material that can be altered to allow the diameter of the lumen to be varied. Upon termination of the alteration, the diameter of the lumen is returned to its normal profile conformation. The cannula according to the invention can be inserted into an object in need of cannulization.
In some embodiments, the cannula also includes one or more mechanisms that allow the diameter of the lumen to be altered. Suitable mechanisms may include coils; springs; extensible, compressible, or releasable wings; foils; folds; and/or cages. Upon release of the mechanism(s), the cannula will either return to its normal profile conformation or expand to the diameter of the surrounding vessel or environment.
In other embodiments, the diameter of the lumen at the point of insertion is narrower than the diameter at the proximal and distal ends. The diameter at the proximal and distal ends of the cannula can either be the same or different. In other embodiments, the diameter at the distal end is greater than the diameter at the point of insertion.
In still other embodiments, the proximal end of the cannula is coated with a water-tight coating, such as a plastic.
The cannulas according to the invention are characterized by a high flow rate of fluids through the cannula. For example, the flow rate of fluids though the cannula may range between 100 mL/min and 6 L/min.
In another aspect, the invention involves a cannula having a cannula body, a distal end, a proximal end, and a lumen with a variable diameter extending between the proximal and distal ends. In one embodiment, the cannula has a narrow diameter at the point of insertion, and, in another embodiment, the diameter of the lumen distal to the point of insertion expands to be the same as the diameter of the lumen proximal to the point of insertion. In a further embodiment, the diameter of the lumen distal to the point of insertion is greater than the diameter of the lumen at the point of insertion. In yet another embodiment, the lumen diameter distal to the point of insertion is expandable to the diameter of a vessel of the patient. In a further embodiment, the proximal end of the cannula is coated with a water-tight coating, such as a plastic.
In yet another aspect, the invention involves a cannula having a cannula body, a distal end, a proximal end, a lumen with a variable diameter extending between the proximal and distal ends, as well as one or more mechanisms that allow the diameter of the lumen to be altered. In various embodiments, the mechanism(s) may include coils; springs; extensible, compressible, or releasable wings; foils; folds; and/or cages. In one embodiment, the cannula will return to its normal profile conformation upon release of the mechanism. In another embodiment, the cannula will expand to the diameter of the surrounding vessel or environment upon release of the mechanism.
In another embodiment, the diameter of the lumen at the point of insertion is narrower than the diameter of the lumen at the proximal and distal ends of the cannula. The diameter of the lumen at the proximal and distal ends may be the same or different. Additionally, the diameter of the lumen at the distal end can be greater than the diameter at the point of insertion.
In a further embodiment, the proximal end of the cannula is coated with a water-tight coating, such as a plastic.
In a further aspect, the invention provides methods of using the cannulas of the invention. In one embodiment, the invention involves the steps of placing the cannula in its low profile conformation, inserting the cannula, and returning the cannula to its normal profile confirmation and allowing the cannula to expand distal to the point of insertion. In another embodiment, the invention involves the steps of activating one or more of the cannula""s diameter varying mechanism(s), inserting the cannula, and deactivating the mechanism(s), thereby allowing the cannula to expand distal to the point of insertion. In this embodiment, the mechanism(s) can be coils; springs; extensible, compressible, or releasable wings; foils; folds; and/or cages.
Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, suitable methods and materials are described below. All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety. In case of conflict, the present specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and are not intended to be limiting.
Other features and advantages of the invention will be apparent from the following detailed description and from the claims.